37
By comparing the actual temperature in relation to the set point on
the thermostat control knob. The thermostat control knob regulates
the temperature to between approximately 40
o
C to 85
o
C.
Once the maximum set temperature has been achieved the burner
switches off. To avoid rapid burner cycling the re-ignition of the
burner can be delayed between 30 seconds and 3 minutes.
When the boiler switches off because either the time clock or room
thermostat is satisfied there is a pump over run which is adjustable
between 0 to 5 minutes to avoid residual heat build up.
Hot Water Mode (with no water flow rate)
When the storage temperature of the tank (measured by the uppper
NTC on the tank) is 4
o
C or more below the set point of the hot water
control thermostat the appliance operates to recover the storage
temperature. The 3 way valve moves into the DHW position, the
pump runs, the burner lights and the ionisation electrodes detect the
prescence of a flame. The primary water is pumped around a
calorifier in the storage cylinder and heats the water indirectly. The
upper NTC continues to monitor the cylinder temperature and
modulates the burner via the gas valve. The flow NTC limits the
temperature to 85
o
C.
When the cylinder temperature is equal to the set temperature the
burner switches off and the pump stops. If the primary water
temperature is greater than or equal to 85
o
C the fan over runs until
the primary temperature drops to 80
o
C to avoid residual heat build
up.
Hot Water Mode (with water flow rate)
With a draw off rate equal to or greater than 1.9l/min:
When the domestic hot water flow switch detects a water flow rate
the 3 way valve moves into the DHW position, the pump, fan and
controls operate and the burner lights. The upper NTC on the
cylinder regulates the temperature of the hot water by adjusting the
modulation rate of the gas valve. If whilst drawing DHW the
difference in temperature monitored between the upper NTC and
the lower NTC on the cylinder is equal to or greater than 1
o
C the
electronics increases the the output of the appliance to anticipate
the reheating of the cylinder. The lower NTC is therefore used as a
booster.
After drawing DHW the fan over runs if the primary water is equal to
or greater than 85
o
C.
Hot Water Mode (with water flow rate)
With a draw off rate equal to or less than 1.9l/min:
With a DHW flow rate insufficient to operate the DHW flow switch
the upper NTC measures the temperature of the water in the
cylinder. If the
∆
T
o
is equal to or greater than 5
o
C in relation to the
thermostat set point, the 3 way valve moves into the DHW position,
the controls and systems operate and the burner lights. The upper
NTC regulates the temperature of the DHW in relation to the
thermostat set point. When the set point is reached the burner
switches off and the fan over runs if the primary water temperature
is equal to or greater than 85
o
C.
Summary of Contents for GENUS 30 Plus
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